Dendrites are typically broad where they
arise from the cell body; away from the cell body they typically taper and
branch. Dendrites may extend up to a millimeter or two away from the
cell body, seldom more. At the magnification shown here, the full
extent of these dendrites would form a halo around your monitor. Dendritic
spines represent a particular type of site for synaptic contact; they are
characteristic of some but not all dendrites.

The axon (singular, one per nerve cell)
is typically uniform in diameter (i.e., not tapering away from the cell
body) and relatively unbranched (at least in the vicinity of the cell body).
usually comparatively narrow. Axons may be many centimeters in length,
up to more than a meter. This length is outrageously long, at least
in terms of ordinary cellular dimensions. At the magnification shown
here, the axon might extend out the door and into the next building.

For scattered individual nerve cells, the Golgi stain renders details
of axon and dendrites in crisp black. But intervening nerve cells
(both neurons and glia) remain unstained and invisible. This invisibility
of most cells is both a strength and a weakness of Golgi stains. If
all cells were similarly stained, the entire specimen would be opaque black
and useless. But with only random individual cells stained, the relationships
between cells (e.g., the fact that there is an axon terminal associated with
each dendritic spine) are obscure.